Sailboards of one type are comprised of a thin elongated hull having a core of floatable material, such as styrofoam. A fitting is provided on the hull in order to support a mast.
U.S. Pat. No. 4,276,844, Fremont, discloses a sail board hull of foam polyurethane with fiberglass cover. The hull has box with a flange sealed to the shell of the board, for receiving a mast. The mast box of this reference is open only at its top.
U.S. Pat. No. 4,579,074, Camp et al, discloses a sailboard in which a mast box is embedded in the hull of the sailboard. The mast box has an inverted T shaped groove, the groove having an upper surface flush with the board. The T shaped groove receives a shoulder bolt adapted to support the mast. The shoulder bolt can be either attached directly to the mast, or indirectly connected to the mast via a rubber power joint of hour glass shape.
U.S. Pat. No. 4,730,568, Campbell, discloses a sailboard having an insert removably mounted to its upper surface, for conversion of the sailboard between a sailboard mode and paddle-ski mode. In the sailboard mode, the insert exposes a recessed rail for receiving a mast base.
In the mounting of a sail to a sailboard, it is desirable, and in some cases mandatory, to provide means for tethering the mast to the sailboard, in order to ensure that the rigging does not float away from the board in the event, for example, that the sailboard is upset in use. A cord or leash line for serving this function is depicted in the 1992 "Sailboard Buyer's Guide and Catalog", Sailboard Warehouse, Inc, Saint Paul, Minn. for example at page 60, wherein the cord is affixed to the mast foot or base and adapted to be connected to the mast via a pin through the latter.
Other mast mounting arrangements are disclosed, for example, in U.S. Pat. No. 4,526,120, U.S. Pat. No. 4,527,499, U.S. Pat. No. 4,558,655, U.S. Pat. No. 4,653,416, U.S. Pat. No. 4,679,516, and U.S. Pat. No. 4,735,163.